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Compound action potential inhibition produced by various antidepressants in the frog sciatic nerve
Ryo Hirao1, Tsugumi Fujita1, Aiko Sakai1
1Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
European Journal of Pharmacology
|December 6, 2017
Summary
Several antidepressants, including duloxetine and amitriptyline, were found to inhibit nerve conduction. Their efficacy in blocking action potentials is comparable to antiepileptics and local anesthetics, suggesting a mechanism for their analgesic adjuvant effects.
Area of Science:
- Neuroscience
- Pharmacology
Background:
- Nerve fiber conduction inhibition may contribute to analgesic effects of certain drugs.
- The comparative extent of conduction inhibition by various analgesic adjuvants is not fully understood.
Purpose of the Study:
- To investigate the effects of different antidepressants on nerve action potential conduction.
- To compare the efficacy of antidepressants in inhibiting nerve conduction with other known analgesic adjuvants.
Main Methods:
- Compound action potentials (CAPs) were recorded from frog sciatic nerves using the air-gap method.
- The inhibitory effects of six antidepressants (duloxetine, fluoxetine, amitriptyline, desipramine, maprotiline, trazodone) on CAP amplitude were measured.
- Half-maximal inhibitory concentrations (IC50) were determined and compared to previously reported data for other drugs.
Main Results:
- Duloxetine (0.23 mM) and amitriptyline (0.26 mM) showed potent inhibition of CAPs, comparable to antiepileptics and local anesthetics.
- Fluoxetine (1.5 mM), desipramine (1.6 mM), maprotiline (0.95 mM), and trazodone (~1.0 mM) exhibited moderate inhibition, similar to some local anesthetics and alpha-2 adrenoceptor agonists.
- All tested antidepressants inhibited nerve conduction to varying degrees.
Conclusions:
- Six antidepressants demonstrated the ability to inhibit nerve conduction (CAPs).
- The efficacy of these antidepressants in inhibiting nerve conduction is comparable to that of certain antiepileptics, alpha-2 adrenoceptor agonists, and local anesthetics.
- This nerve conduction inhibition may contribute to the analgesic adjuvant properties of these antidepressants.
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